Plain English Meaning
A simple drawing made of three arrows that shows where the aircraft is pointing, where the wind is pushing it, and where it actually ends up going. By drawing or calculating these three arrows together, a pilot can figure out the heading to fly and how fast they will travel over the ground.
Full Definition
A graphic representation of the relationship between an aircraft's heading and true airspeed, the wind direction and speed, and the resulting track and groundspeed. The three vectors form a triangle that allows a pilot to solve for any unknown side or angle when the other elements are known.
Context Anchor
Seen in cross-country flight planning, calculations, and discussions of and groundspeed.